* either express or implied. See the License for the specific language
 * governing permissions and limitations under the License.
 */
package org.codelibs.core.beans.impl;

import static java.util.Collections.unmodifiableCollection;
import static org.codelibs.core.collection.CollectionsUtil.newArrayList;
import static org.codelibs.core.collection.CollectionsUtil.newHashMap;
import static org.codelibs.core.collection.CollectionsUtil.newHashSet;

      return unmodifiableMap(Maps.transformValues(super.rowMap(), Collections::unmodifiableMap));
    }

    @Override
    public Collection<V> values() {
      return Collections.unmodifiableCollection(super.values());
    }

    @GwtIncompatible @J2ktIncompatible private static final long serialVersionUID = 0;
  }

  /**

 *
 * <ul>
 *   <li><b>Shallow immutability.</b> Elements can never be added, removed or replaced in this
 *       collection. This is a stronger guarantee than that of {@link
 *       Collections#unmodifiableCollection}, whose contents change whenever the wrapped collection
 *       is modified.
 *   <li><b>Null-hostility.</b> This collection will never contain a null element.

 *
 * <ul>
 *   <li><b>Shallow immutability.</b> Elements can never be added, removed or replaced in this
 *       collection. This is a stronger guarantee than that of {@link
 *       Collections#unmodifiableCollection}, whose contents change whenever the wrapped collection
 *       is modified.
 *   <li><b>Null-hostility.</b> This collection will never contain a null element.

    return unmodifiableCollectionSubclass(output);
  }

  <E extends @Nullable Object> Collection<E> unmodifiableCollectionSubclass(
      Collection<E> collection) {
    return Collections.unmodifiableCollection(collection);
  }

  @Override
  public void clear() {
    // Clear each collection, to make previously returned collections empty.
    for (Collection<V> collection : map.values()) {